Supplementary Material for: Effect of Enteral Vitamin A on Fecal Calprotectin in Extremely Preterm Infants: A Nested Prospective Observational Study

Background: Vitamin A has anti-inflammatory and immune-modulating properties. We aimed to assess whether enteral water-soluble vitamin A supplementation in extremely preterm infants decreases fecal calprotectin, a marker of intestinal inflammation. Methods: This was a prospective observational study nested in a randomized, double-blind, placebo-controlled clinical trial investigating enteral vitamin A (5,000 IU/day) for reducing the severity of bronchopulmonary dysplasia (BPD) in extremely preterm infants. Fecal calprotectin levels were measured using enzyme-linked immunosorbent assay after 28 days of Vitamin A or placebo supplementation. Results: Fecal calprotectin was measured in 66 infants (Vitamin A: 33, Placebo: 33). The mean (standard deviation) gestational age (25.5 [1.55] vs. 25.8 [1.48]; p = 0.341) (week), birth weight (810 [200] vs. 877 [251]; p = 0.240) (gram), and factors influencing fecal calprotectin levels were comparable between the vitamin A versus placebo group infants. All infants were exclusively fed with mother’s or donor’s human breast milk if mother’s milk was unavailable using a standardized feeding regimen and received prophylactic probiotic supplementation. Fecal calprotectin levels (median; 25th–75th centiles) (micrograms/gram of feces) were not significantly different between vitamin A (152; 97–212) and placebo groups (179; 91–313) (p = 0.195). Two infants in the vitamin A group developed definite necrotizing enterocolitis compared to none in the placebo group. Incidence of BPD at 36 weeks postmenstrual age was similar between the groups (vitamin A: 18/33, placebo: 13/33, p = 0.218). Conclusion: Enteral supplementation with water-soluble vitamin A did not affect fecal calprotectin levels in extremely preterm infants. Studies with a larger sample size are required to confirm the findings.研究背景：维生素A具有抗炎与免疫调节活性。本研究旨在评估极早早产儿接受肠内水溶性维生素A补充疗法后，其粪便钙卫蛋白（fecal calprotectin，一种肠道炎症标志物）的水平变化，明确该干预是否可降低粪便钙卫蛋白水平。研究方法：本研究为一项前瞻性观察性研究，嵌套于一项针对极早早产儿肠内维生素A（每日5000 IU）干预以降低支气管肺发育不良（bronchopulmonary dysplasia, BPD）严重程度的随机双盲安慰剂对照临床试验。在维生素A或安慰剂补充治疗28天后，采用酶联免疫吸附试验（enzyme-linked immunosorbent assay）检测粪便钙卫蛋白水平。研究结果：本研究共纳入66例婴儿，其中维生素A组与安慰剂组各33例。两组婴儿的平均（标准差）胎龄[25.5（1.55）周 vs. 25.8（1.48）周；p=0.341]、出生体重[810（200）g vs. 877（251）g；p=0.240]，以及影响粪便钙卫蛋白水平的相关因素均无统计学差异。所有婴儿均采用标准化喂养方案，仅使用产妇母乳或当产妇母乳不可得时使用捐赠者母乳进行纯母乳喂养，并接受预防性益生菌补充治疗。两组粪便钙卫蛋白水平[中位数（25th~75th百分位数），单位：微克/克粪便]无显著统计学差异：维生素A组为152（97~212），安慰剂组为179（91~313），p=0.195。维生素A组有2例婴儿确诊为坏死性小肠结肠炎（necrotizing enterocolitis），安慰剂组未出现该病例。两组校正胎龄36周时的支气管肺发育不良发生率无显著差异（维生素A组18/33，安慰剂组13/33，p=0.218）。研究结论：肠内水溶性维生素A补充疗法并未对极早早产儿的粪便钙卫蛋白水平产生显著影响。未来需开展更大样本量的研究以验证本研究结论。